Conventional strain relief devices for electrical cables clamp the cables against the connector housing and/or other adjacent cables down line from the delicate terminations made within the connector. This way, strain on the cable is diverted to the connector housing before reaching the terminations. This minimizes the stress imposed on the terminations within the connector and thereby prevents faulty electrical contact and breakage.
Effective strain relief of ribbon cables is a more demanding task due to the nature of the connector and the large number of conductors typically existing in a ribbon cable. Ribbon cables may include hundreds of side-by-side conductors joined by a ribbon binder. Such cables are typically terminated in single or multiple rows of insulation displacing contact terminals seated within narrow elongate connector housings. The ribbon cable is pressed in place against the contact terminals, and the terminals pierce the insulating binder to make contact with the conductors therein. The resulting compression-type terminations are prone to strain when the cables are pulled or twisted. Consequently, it is essential to incorporate some form of strain relief in the connector assembly to protect the terminations.
For example, U.S. Pat. No. 5,011,430 issued to Haitmanek shows an electrical connector assembly for terminating a flat multi-conductor ribbon cable. The connector assembly includes an elongate housing in which a plurality of insulation displacing contacts is arrayed. Strain relief is provided to the portions of the cable exiting the connector by spring clips that clamp the cable against a side wall of the housing. Unfortunately, the Haitmanek '430 strain relief is integral to a particular connector assembly and cannot be retrofit to an existing connector. Moreover, metal spring clips are required. These clips are difficult to manufacture, and special tooling is required for assembly.
U.S. Pat. No. 4,255,205 issued to Sinclair et al. discloses a ribbon cable connector with two pivoting flaps which clamp the ribbon cable therebetween. Strain relief is provided by a plurality of posts which penetrates the binder down line of the terminations and by protruding ribs which are compressed against the ribbon cable. The Sinclair et al. '205 connector is easy to apply and such may be accomplished manually. However, the Sinclair et al. '205 strain relief is still integral to the particular connector assembly and cannot be retrofit to an existing connector.
U.S. Pat. No. 3,879,099 issued to Shaffer discloses a ribbon cable connector with pivoting flaps which bias the insulation displacing contacts against the ribbon cable, thereby completing the terminations. In addition, the flaps protrude beyond the contacts and interlock down line therefrom to provide a measure of strain relief. Again, the Shaffer '099 strain relief is integral to the particular connector assembly and cannot be retrofit to an existing connector.